<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>10_固定定位</title>
    <style>
        .fu{background-color: #ff0;}
        .fu>div{width: 100px;height: 100px;}
        .z1{background-color: #f00;}
        .z2{background-color: #0f0;
            /*固定定位：会脱离文档流 释放布局空间
            移动参照物：html根元素
             */
        position: fixed;
        right: 0;
        bottom: 0;}
        .z3{background-color: #00f;}
    </style>
</head>
<body>
<div class="fu">
    <div class="z1"></div>
    <div class="z2"></div>
    <div class="z3"></div>
</div>
</body>
</html>